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## Homework Statement

4.20g of nitrogen gas at 22.0 C and an initial pressure of 2.30 atm undergo an isobaric expansion until the volume has tripled.

A.)How much heat energy is transferred to the gas to cause this expansion?

b.)The gas pressure is then decreased at constant volume until the original temperature is reached. What is the gas pressure after the decrease?

c.)What amount of heat energy is transferred from the gas as its pressure decreases?

## Homework Equations

Pv=nRT

W=-p(delta V)

## The Attempt at a Solution

Ok so here is all of the steps that I take. I know it seems like I do more then I need to but I get all of the information I can in these problems so that I can memorize the ways to do it so here goes.

First the infromation that I have is

M = .0042kg

R=8.31

Ti = 295K (22+273)

Pi= 2.3 atm = (101325 * 2.3) = 233047.5

An= 14u = (14 * 1.661 x 10^-27) = 2.33 x 10^-26 Kg

M/kg = 2.33 x 10^-26 * 6.02 x 10^23 = .014 Kg

n= .3 mol

Vi= (.3 * 8.31 * 295)/233047.5 = .00315 m^3

Vf= .00315 * 3 = .00947

This is where I'm having a hard time. The equation I have tried using is

W=-p(delta V)

-233047.5 * (.00315 - .00947) = 1472.86 (this answer is wrong)

So what am I doing wrong?

So here is some more work that I have doen.

W=nR(deltaT) = 590.79

Tf= 590.79 + 22 = 612 C = 612 +273 = 885 K (That seems a little hot I'm pretty sure its not right but I can' get any other answer.)

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